Tuesday, February 23, 2010

Franklin, TN - RTM Productions and Year One present the Year One “Track Car Giveaway”, a six month sweepstakes awarding the lucky winner a replica ‘68 Mustang track car built on SpikeTV’s PowerBlock shows HorsepowerTV and MuscleCar.

“We want to salute the American muscle car and the men who built speed parts for them and then raced these iconic machines. Vic Edelbrock is one of those guys who is still doing that today so we created this car as a tribute to his career.” said Year One President Kevin King. The car carries Edelbrock’s #27 race number.

Built with parts from Year One’s Mustang catalog, it features a Dynacorn uni-body, Global West suspension, Wilwood brakes, Flaming River steering and BF Goodrich race tires. It’s powered by a Ford Racing 347 stroker with a Competition Cams valve train and Edelbrock cylinder heads, intake and carburetor. The winner of the car will also receive a helmet and driving suit from Race-Quip. The sweepstakes runs through July 15, 2010. Kevin King will award the car to the winner on September 28 and that presentation will air on PowerBlock November 20-21.

“We’ve experienced a lot of viewer interest in Year One inspired sweepstake cars. Our last collaboration – the ’69 “Crate Camaro” received 1.2 million entries. We believe this unique car will exceed that.” added RTM executive producer Joe St. Lawrence.

The promotion will be advertised on HorsepowerTV, Trucks!, Xtreme 4x4 and Muscle Car TV shows as well as in PowerBlock the Magazine, powerblockTV.com and the mypowerblock.com social community. It is open to US and Canadian residents.

RTM is a privately held marketing solutions company specializing in creating automotive content for distribution through television, web, magazine and DVD distribution. For Official Rules visit PowerblockTV.com, YearOne.com or Edelbrock.com.

Gearing a Classic Camaro for Road Racing

As many enthusiasts will tell you, nothing tops the experience of driving their favorite Chevy along a twisty road, whether the car is a late model or a modern-equipped classic.

And when taking such drives, a manual transmission is practically a must … and the more gears, the better.

For that matter, when was the last time you saw a road race in which a car with an automatic transmission beat its manual-transmission competition? Most likely, never. Manual transmissions dominate the road race and autocross circuits, as well as the drag strip.

So it was no surprise to Craig Hurst, marketing/parts manager for Guldstrand Motorsports (Burbank, California), when a customer whose ’69 Camaro the shop was setting up for road racing wanted them to install a Keisler Engineering five-speed manual transmission.

“We’d already installed SPC Performance’s adjustable upper control arms, Pro Springs and front sway bar, new QA1 Motorsports shocks, and Wilwood disc brakes all the way around,” Hurst said. “The car has a 502 V-8 putting out 570 lb-ft torque, but it had an old Muncie M20 four-speed. So the Tremec PerfectFit™ TKO-600 five-speed transmission, which can handle up to 600 lb-ft torque, was a perfect upgrade.”

Keisler Engineering in Knoxville, Tennessee, started in October of 1991 as an electrical component restoration company for 1960-1970s Mopar cars. By the mid-’90s, Keisler had grown to include reproduction molded lamp lenses for those same Mopar cars. By the end of the decade, they developed a complete, modern-technology, five-speed conversion kit for the Jaguar V-12, and then several Mopar drivetrains, all of which became successful worldwide.

Since then, Keisler has continued to develop a full line of retrofit manual and automatic transmission kits with that same commitment to engineering excellence, including a line of Tremec direct-fit replacement kits for most popular Mopar, Ford, and GM vehicles. Keisler is an authorized Tremec distributor, and they service their products in house, under full Tremec warranty, to avoid hassles. Keisler also provides a two-year window for installation before the warranty activates.

Aside from unexpected problems caused by the old bell housing and an unusually thick flywheel, the installation was a breeze, and everything fit perfectly. It’s unlikely such problems would be encountered often, but the solutions were simple. Follow the photos as Mark Duncan and Dick Guldstrand show you how simple it is to gear up for road racing with Keisler.

1 A Keisler Tremec TKO-600 five-speed for 1967-’69 Camaro/Firebird (with a .64 overdrive) was ordered, along with a new crossmember and driveshaft. The transmission can also be ordered as a complete kit that includes a new shifter kit, bell housing, flywheel, clutch and much more.

2 The Muncie four-speed had an old GM bell housing with such a large center hole that it had totally fried the pilot bearing; new pilot bearing was installed and a Classic Industries 11-inch, high-performance bell housing (P/N 14053) was chosen.

3 To check concentricity of the new bell housing, a steel plate was bolted to the flywheel to provide a flat surface for the magnetic base of the dial indicator.

4 The new bell housing was bolted up, a dial indicator was attached, and the concentricity of the bell housing and alignment of the center bore with the crankshaft were checked by rotating the engine one full revolution and marking the runout at eight different points. Total indicated runout (TID) was less than 0.005 inches, well within limits.

5 The Camaro also had a McLeod RST twin-disc clutch assembly, which Guldstrand sent to McLeod to have rebuilt to match the requirements of the new transmission. Then it was assembled for mounting and an old output shaft inserted to help seat and align the clutch assembly.

6 The clutch was then aligned with the flywheel, using the mark made showing the original position, and loosely bolted to the flywheel. (Note: Duncan puts blue Loctite on all bolts before installing them.)

7 The flywheel bolts were then tightened (in a star pattern) to proper specs with a torque wrench.

8 Duncan then slipped the new bell housing in place and bolted it up to the engine. He then tightened the bolts to spec with a torque wrench.

9 The next step was to use a straight edge and ruler to measure the distance from the transmission mounting surface of the bell housing to the point of the clutch fingers that contact the release bearing.

10 Then, with the combination concentric slave cylinder (CSC) release bearing fully compressed, the distance from the transmission mounting surface to the straight edge was noted. There was less than the 1/8-inch extra room needed to keep the clutch from bottoming out from disc wear and expansion from heat. The solution was to remove the extra-thick flywheel and shave it 0.100 inch. The flywheel is still 0.550-inch thick at its thinnest point.

11 The supplied high-pressure hose (with bleeder) was then installed in the CSC, being careful not to cross-thread the fitting.

12 Next, Guldstrand stepped in to finish the installation, first jacking the transmission up in place and bolting it (loosely) to the bell housing.

14 Next, the new Keisler crossmember was slipped in place over the frame rails and bolted (loosely) through the existing frame holes.

15 An Energy Suspension polyurethane transmission mount (set #3-1108) was then attached (loosely) to the transmission and crossmember.

16 The jack was lowered, and the lines and hoses attached. The driveshaft will be installed after some third-member work is done, at which time everything will be aligned and all bolts tightened to proper torque specs.

17 At press time, the owner of the car hadn’t decided which shifter he wanted to use. Dick offered a suggestion … but maybe not.

SOURCES

Keisler

(888) 609-0094

Guldstrand Motorsports

(818) 558-1499

www.guldstrand.com

McLeod

(714) 630-2764

www.mcleodind.com

Classic Industries

(800) 854-1280

www.classicindustries.com

Energy Suspension

(888) 913-6374

www.energysuspension.com

The article featured on this page is from the February 2010 issue of Chevy Enthusiast Magazine.

Tuesday, February 9, 2010

1 The lever-type battery disconnect switch; it has more electrical contact surface and is easy to operate, but it’s bulky and requires more operating clearance.

2 The “green knob” disconnect switch; it’s compact, but you need to ensure that the knob is loose enough to open the circuit and is tight enough to make good contact when closing the circuit.

Battery Disconnect Switch for your Corvette.

Self-inflicted Open-circuit

John Hinckley

Reader’s Question:

I know it’s a good idea to disconnect the battery when you’re working on anything electrical, but it’s inconvenient to remove the cable terminal from the battery every time I work on my ’66. I see two types of battery disconnects for sale – the one with a green knob, and the one with a lever on it; is there any difference between them, and should they be installed on the positive terminal or on the ground terminal?

Response:

A battery disconnect switch makes it convenient to isolate the battery from any potential ignition-off draws (like a glove box light that doesn’t turn off) during storage, and it’s much more convenient to turn a knob or move a lever than to keep removing the cables from the battery terminals.

You also want to remove the battery as a power source when doing any work on the car that involves the electrical system, especially on earlier cars that have many unfused, ignition-off, battery-fed circuits and don’t have fusible links on the primary power feed circuits; harnesses are expensive, and dead shorts can cause a fire.

There are proponents for both types of disconnect switches, and both types have their pros and cons. The “green knob” disconnect is smaller and takes up less space, but you need to make sure you have the knob unscrewed sufficiently to open the circuit when disconnecting, plus the knob must be tightened firmly for good contact when re-connecting. It also has the advantage of being a theft deterrent if you remove the knob entirely and take it with you.

The lever type has more contact surface between the lever and the receiver legs for reduced resistance. It’s more visually obvious when it’s open or closed, and it only requires a single, simple motion to operate it. However, it’s bulkier and can present installation/operation clearance issues where batteries are tightly packaged (like on ’68-’82s).

Both types are designed to be installed on the negative battery terminal; the negative battery post is smaller in diameter than the positive post, and the disconnects have the smaller hole where they attach to the battery (and the smaller post size where the negative cable attaches to the switch). Why?

If you switch the positive side, it kills the power to the harnesses, but a ground path still exists back to the battery; if you drop a wrench and it touches the battery positive terminal and the engine, it’ll create a 500-700-amp dead short you’ll never forget, and it could damage (or destroy) the battery.

If you switch the negative side (as all the disconnects are designed to do) and drop a wrench that touches the battery positive terminal and the engine, nothing will happen, as there is no ground path from anything in the car back to the battery to complete the circuit. That’s why the disconnects are designed to be installed on the negative (ground) side of the battery.

Which type you choose is a matter of personal preference, but by all means install one; they’re a great convenience.

Audio Upgrade for a Classic Chevy

Ken Harrison Enterprises bring the audio in this 1965 Chevy Impala into the 21st Century.

Text by Richard Truesdell / Images by Amy Sprunger

Tom Baumgartner has owned the 1965 Chevy Impala pictured here since he was 16 years old.

It holds a cherished place among the cars in his collection and after a complete restoration that took more than five years, it’s a car he loves driving when weather permits. But after dealing with a period-correct AM radio, he finally decided that it was time to upgrade the audio system. For that, he turned to Ken Harrison Enterprises of Texas for the components for a non-invasive installation that left the Impala virtually untouched.

Many classic and special interest car owners are reluctant to make any permanent modifications to their cars, especially in visible areas like the interior. This makes it difficult to install modern car audio components, especially head units, as most of the mainstream manufacturers (Alpine, JVC, Kenwood, Pioneer and Sony to name a few) discontinued production of traditional shaft-mount radios almost two decades ago. This has left this small niche market to be served by specialty manufacturers, and among these companies, Ken Harrison is held in high regard, especially within the classic Chevy community.

For this installation, Ken Harrison supplied with their shaft-mount 200-watt KHE-300 AM/FM head unit with front and rear auxiliary inputs (suitable for MP3 players and external satellite radios from Sirius and XM). The KHE-300 is the control center for the system and features adjustable shafts and a small nosepiece with an analog station display with a digital clock that fits through the factory opening without any modifications.

The control unit for the separate trunk-mounted FM-modulated 12-disc CD changer would be mounted by installer Josh Perkins in the glove compartment for a stealth-looking installation. Rounding out the installation would be the replacement of the single mono in-dash speaker with a pair of smaller 3½-inch speakers mounted on a plate. While the rear-mounted 6 x 9s would provide the system with much better fidelity, such as the ability to play loud enough when driven by the 50-watt-per-channel four-channel amp built into the KHE-300.

If you have a classic Chevy and want a non-invasive installation of a modern audio system, check out the line of available components from Ken Harrison Enterprises of Texas (www.oldcaraudio.net). Available for many classic Chevys, these components are also sold by independent retailers.

1 The starting point for this classic Chevy audio upgrade is straightforward: a traditional full-size Sixties GM dash. The radio and glove box have already been removed from the dash of the 1965 Impala.

2 Here’s the replacement KHE-300, a traditional shaft-mount radio with a separate nosepiece, designed to fit the Impala’s radio opening with no cutting or modifications.

3 Installer Josh Perkins is getting the replacement 3½-inch speakers mounted and wired, replacing the single monophonic speaker. This needs to be completed before mounting the new radio. Having the glove box already removed makes this task much easier.

4 Josh prepares the power and ground leads. Unlike the original radio, the KHE-300 will require a new lead, wired to a constant 12-volt source, to power the KHE-300’s built-in clock.

5 Now we’re making progress, a test fit of the new radio. This is essential: given that the mounting points for each shaft are different, requiring a different stagger for each, an adjustment made by nuts and washers on each shaft.

6 Once the mounting of the radio is confirmed, it’s time to tighten up all the screws that attach the original trim bezel to the instrument panel. A stubby screwdriver makes short work of this task.

7 Now that the radio is secured to the dash and the knobs are installed, the KHE-300 looks as if it was designed by the factory for the 1965 Impala.

8 Since new rear speakers will be installed, Josh starts the process of running new speaker wires, starting at the back of the radio and running the wires under the carpet to the rear of the car.

9 This step is more crucial than it looks. Make sure that when running the wires to the rear, you don’t accidentally screw through the speaker wires or any cables, such as for a CD changer, when you reinstall the threshold plates.

10 With all the wires and cables run front to rear, Josh has started to install the control unit for the trunk-mounted CD changer in the Impala’s glove box.

11 The controller for the Pioneer CD changer, the output of which interfaces with the KHE-300 via an FM modulator through the antenna input, is installed in the glove box.

12 The CD changer will be installed under the rear deck, requiring Josh to show his abilities as a contortionist.

13 After the brackets have been attached to the CD changer, the entire assembly is secured to the underside of the rear deck.

14 Once installed, the CD changer is unobtrusive, yet it’s easy to change the 12 discs loaded into the cartridge.

15 Believe it or not, the Impala has provisions for two 6 x 9 speakers, which can be mounted from the top with the supplied grilles – as shown here – or from the bottom for a more custom appearance.

16 With all the components installed, we’re ready to test the system. Note the front panel AUX-in, suitable for use with a portable MP3 player or even an external satellite radio tuner.

17 The KHE-300 looks as if it could have been factory-installed back in 1965.

18 The Pioneer CD changer package is supplied with a credit card-sized remote control, which can be used to access the discs in the trunk-mounted changer.

19 Once the glove box door is re-installed and closed, the installation of the controller for the CD changer is totally stealth.

Wednesday, February 3, 2010

Four-Barrel Fundamentals 12 great setup and tuning tips for the Holley carburetor

Story and photography by Barry Kluczyk

Sure, we know the standard carburetor on just about every performance Poncho was a Rochester. But when it comes to building higher-performance engines, many turn to the venerable Holley four-barrel.

But in this age of electronic fuel injection, however, fewer and fewer enthusiasts know their way around the venturis, jets and power valves of a traditional carburetor. In fact, the perception that setting up and tuning a carburetor is complicated for those with limited experience is enough to turn them off altogether.

It’s true that the variety of adjustable components on a typical four-barrel carburetor allows for an almost infinite number of tuning scenarios, but there are a few basic steps to help select, set up and tune your carb with surprising precision. In fact, even if you’ve never turned a screw on a Holley four-barrel, you should feel confident about installing one and getting your engine to run and idle very close to an optimal tune.

For this story, the tips are based on applications using a Holley 4150/4160-type vacuum-secondary four-barrel (the non-Dominator-type), but most are applicable to other popular carburetors – even singe- or two-barrel models, as well. And to illustrate the tips more clearly, we’ve posed the carb on a Professional Products Hurricane 326-455 intake manifold (part number 56031).

With the following dozen tips to guide your way, you’ll have that carburetor breathing right and giving your Pontiac the crisp, immediate throttle response that just isn’t available with electronic fuel injection.

1. Don’t super-size it. When selecting a carburetor for your engine, don’t overdo it. Generally speaking, a mild-to-moderate street engine doesn’t need more than a 650- or 750-cfm carburetor. To zero in on the most appropriate carb size, multiply the cubic-inch displacement and maximum rpm and divide the product by 3,456. For example: a 350 engine multiplied by a 5,500-rpm redline and divided by 3,456 equals 557, or at least 557 cfm. In that case, a 650-cfm carb is sufficient. It’s OK to go a littlelarger than necessary, but don’t choose a carb that’s rated at less than the minimum requirement.

2. Timing is everything. If the first couple of starts don’t produce a quick firing and idle – even if they’re not perfect – don’t jump to the conclusion that it’s a carb-tuning problem. A hard-starting scenario could very well be due to improper ignition timing. So, before cursing the carburetor as you’re ripping it off the intake manifold, double-check the ignition timing. Even an inaccuracy of only a few degrees could produce a hard-start/no-idle condition.

3. Vacuum secondaries vs. the double-pumper. Here’s a simple formula: Use a vacuum-secondary carburetor on midsize and large cars with an automatic transmission. Go with a “double pumper”-type mechanical-secondary carb when using a manual transmission application or with smaller cars that have a radical cam profile or are going to see a lot of time on the drag strip.

4. Power valve power play. The power valve is a vacuum-activated feature that’s used to enrich the fuel mixture to prevent detonation or stumbling (think “metering rod” on a Carter-style carburetor). They’re available in different sizes to match the flow requirements of the engine. On manual-transmission applications, a standard 6½-inch power valve is adequate if the vacuum reading at idle is above 12 inches. For automatic applications, if the idle vacuum reading is below 12 inches, divide the number in half to determine the correct power valve size. For example: a 9-inch vacuum reading requires a 4½-inch power valve.

5. Installing the electric choke. A key-on hot lead wire is connected to the positive (+) spade on the choke cap; and the negative (-) spade on the choke cap is wired back to the carb as a ground. It sounds simple enough, but many installers get it wrong. Now you don’t have to be one of them.

6. Electric choke fast idle adjustment. With the engine off, hold the throttle wide open; this drops a lever with a ¼-inch screw in it beneath the choke housing. To slow the idle, turn the screw counter-clockwise. Turn it clockwise to increase the idle speed.

7. Basic fuel level adjustment. A too-low fuel level in the fuel bowl can cause stumbling when the throttle is opened quickly. Follow these simple steps to adjust it:

Remove the sight plug on the side of the fuel bowl.

With the engine running, loosen the lock screw on top of the fuel bowl.

Turn the nut on the fuel bowl clockwise to lower the fuel level and counter clockwise to raise the fuel level until the fuel is level with the bottom of the hole.

8. Mixture screw setup: Getting the mixture screw adjusted properly is a must for preventing lean or rich conditions. Follow these steps:

Bring the engine to normal operating temperature and turn it off.

Turn the mixture screws all the way in and, then back them out three full turns.

Restart the engine

With the engine idling at temperature, turn one screw in a quarter-turn and the next screw in a quarter-turn, repeating the process in quarter-turn increments until the engine rpm drops.

When the rpm drops, turn the screws back out a 1/8-turn.

9. Selecting the right-size jets. Whether you call them shooters or jets, installing the correct-size components is essential for smooth operation and stumble-free acceleration. Because every application is different, settling on the correct shooter size (orifice diameter) often comes down to trial and error tuning. Stumbling at take-off without black smoke from the tailpipe means the shooters/jets are too small. Stumbling with black smoke from the tailpipe means the shooters/jets are too large. Crisp, stumble-free acceleration and optimal vacuum mean the shooters/jets are just right.

10. Trouble-shooting bogging and hesitation. Bogging or hesitation is annoying and gives the impression of low horsepower. It occurs when the secondaries come in too soon; and it can be corrected with a heavier secondary spring. Conversely, sluggish performance, especially at wide-open throttle, may be due to a too-heavy secondary spring. Swap in a lighter one.

11. Overcoming stumbling. Stumbling is a common malady experienced with a new or rebuilt carb that makes one wish for electronic fuel injection. But it’s pretty easy to diagnose and cure.

A stumbling condition at take-off is usually due to an inadequate accelerator pump fuel shot – assuming the shooter/jet size is correct (see above). Inspect the pump shot with the engine off. Look into the carb and move the throttle; fuel should spray the instant the throttle is moved. If it doesn’t, turn the nut of the pump arm counter-clockwise one full turn and check the spray again. Continue until the spray is immediate with the throttle. If the pump spray is immediate upon inspection, check the following:

Inspect the pump diaphragm for a hole.

Check the pump passage for debris or other impediments.

12. Dried out. If you’re using an old carburetor that has sat unused for a long time – such as the time it took to remove, rebuild and reinstall the engine – it’s pretty common for the gaskets in the metering block to dry out and/or shrink, causing idle problems. If everything else seems to check out, a rebuild of the carb to replace the old gaskets will likely do the trick.

Overdrive Transmission Compatibility

When using a Holley vacuum-secondary carb on a vehicle with a non-electronic overdrive automatic transmission, such as the 200-4R or 700R-4, a throttle kick-down bracket must be used. Otherwise, the transmission’s throttle valve (TV) cable won’t be positioned properly. When that happens, the transmission will shift too early or too late and the line pressures won’t be correct, which will eventually (and probably quickly) cause catastrophic (and expensive) transmission problems. The brackets are available from a variety of aftermarket vendors, such as TCI and B&M.

1 It’s very easy to over-carb an engine, which makes accurate tuning almost impossible, as the too-large carburetor will simply dump too much fuel into the engine. Follow the sizing formula described in the main text’s #1 tip to zero in on the right size for your engine.

2 Don’t assume a hard-starting or stumbling condition is strictly carb-related. Incorrect ignition timing is a common problem on rebuilt and crate engines. Break out your timing light and double-check the timing before cracking open the carburetor.

3 This may sound beyond basic to many, but you’d be surprised how many people install the carburetor backwards on the first try. Remember: The carb mounts with the throttle linkage on the driver’s side of the engine … err … unless you’re reading this in Australia or Great Britain.

4 This diaphragm identifies this carburetor as one with vacuum-operated secondary venturis. For most automatic-equipped, mild-to-moderate horsepower applications, it’s the way to go. Save the double-pumper carb for manual transmissions and higher-horsepower engines.

5 Access to the fuel jets (also known as shooters or squirters) and power valve is gained by unbolting the fuel bowl (and typically some gentle prying to break the seal of the gasket). Regardless of whether the carb is a double-pumper or vacuum-secondary-type, Holley four-barrels have jets and a power valve behind the fuel bowl on the metering block.

6 With fuel bowl removed, the power valve and jets are easy to reach. They’re attached to another removable component called the metering block. The power valve is the larger, centered component, with the jets located below it.

7 The jets are numbered, with larger numbers indicating larger-diameter orifices for the fuel to flow through. Removal and installation is as easy as screwing them in or out with a flat-blade screwdriver. When changing jets, experiment in small-size increments, as minor jet size changes can have a comparatively large effect on performance.

8 Changing the power valve requires removal of the metering block in order to loosen it from the carb side of the metering block.

9 Look closely at the connection points for the electric choke mechanism and you see “-“ and “+” symbols. The negative spade grounds the choke back to the carburetor, while the positive spade is connected to a key-on hot lead.

10 The fast idle adjustment arm lowers into adjustment position when the throttle is held wide open (with the engine off). It has a screw head on the bottom, but it can be difficult to reach when the engine is installed in the car. You’ll have an easier time with a ¼-inch box-end wrench. Turn the screw clockwise to increase the idle speed and counter-clockwise to reduce it.

11 The first step when it comes to adjusting the fuel level in the fuel bowl is the removal of the sight plug, which simply unscrews from the outside of the bowl. When it is removed, fuel may spill out of the hole, so be prepared with rags around the base of the carb.

12 After the sight plug is removed, the fuel level in bowl is adjusted by turning the nut on the end of the fuel bowl. Every “flat” corner of the nut is equal to a 1/32-inch difference in the fuel level, so a 1/6-turn delivers a 1/32-inch reduction or increase in the fuel level. A matching adjustment should be made to the opposite fuel bowl. (The screwdriver is used to hold the attachment screw in place when turning the nut.)

13 The mixture screws – which ensure the right ratio of fuel to air at idle – are located on both sides of the metering block. Adjustments are made in quarter-turn increments, per the instructions outlined in the main text of this story. Each turn of a screw must be matched to the complementing screw on the other side of the metering block. With a vacuum-secondary carb, these adjustments are only required on the primary side, while double-pumper carbs require the adjustments on both the front and rear metering blocks.

14 Bogging or hesitation can be due to an improperly-tensioned secondary spring, requiring a heavier spring if the secondaries come in too quickly or a lighter spring if wide-open throttle performance seems sluggish. The spring is visible as the cap on the secondary diaphragm is removed. It simply pulls off the cap for replacement.

15 Curing stumbling upon takeoff is possible with adjustment of the spring-loaded accelerator pump arm. Following the instructions outlined in the main text’s #11 tip, hold the bottom of the pump arm with a wrench and make the adjustments on the top nut with a 3/8-inch wrench.

16 Gaskets for the metering block and fuel bowl are prone to deterioration and drying over time. If you’re installing an older carb on your new or rebuilt engine, it’s worth the few minutes to replace the gaskets to ensure a smooth idle and prevent leaks on your shiny, new intake manifold.

Notes on Hemi engine rear details and heat shields

by Frank Badalson

Hey Frank! We’ve got some interesting questions, but this one regarding the rarely seen back of the Hemi motor made me decide to focus on that this month, so we’ll be a little short on text but show you a couple of cool photos; here was the question —

“Do you have any info or photos showing the rear of a ’69 Hemi engine? I need to know how the choke tubes are routed and what holds them in place. Also, any info on the correct installation of the starter heat shield would be appreciated. Thanks!”

Yes, sir, I do happen to have some good photos of the rear of the Hemi engine prior to installation, right from back in the day. Actually, the choke tube routing and the clips that secure the two tubes are the same for all ’66-70 street hemi engines. However, Hemi engines in 1971 did not use choke tubes due to the new-for-’71 manual choke design. I have some really good shots of a 1970 crated engine from Chrysler Corporation from when the engine was just coming out of the crate. It really doesn’t get any better than this. As they say, a photo really is worth a thousand words, especially a correct, accurate photo!

Next, we will address the Hemi starter heat shield question. All Hemi automatics from 1966-69 used a starter heat shield; the ’66-’69 Hemi four-speed cars with the direct drive starter did not use the starter heat shield. However, all 1970 and 1971 Hemi cars (automatics and four-speeds both) used the heat shield. The factory schematic illustration shown here tells the story. Another thing to note is that all starters used a shim or seal between the bellhousing/auto trans case and starter. The 1966-69 four-speed direct drive starter used its own metal shim/seal, but all 1966-71 Hemi automatics and the 1970-71 Hemi four-speeds used a different shim/seal.

As the schematic shows, this shim/seal goes on, then the starter; for automatics, next is the fluid tube retaining bracket, then the starter heat shield. The front upper portion of the heat shield is secured via a special bracket which is installed on the second from the rear exhaust manifold bolt during initial engine assembly. This bracket would have been painted orange when the engine itself was painted. The starter heat shields were assembled to the engine with the starter and positive battery cable, and therefore the heat shields are not engine color. All starter heat shields were painted a semi-gloss black.

PHOTO: Here is the photo of the rear of a 1970-era crate motor; note the tube position and placement. While the photo is not perfect, it is vintage – this is exactly what the 1970 factory choke set-up looks like.

DIAGRAM: This exploded parts diagram shows many of the components associated with the heat shielding on Hemi powerplants. As mentioned, four-speed cars from 1966-69 had the direct-drive starter and did not use the shielding; all other OEM Hemi car received it in one form or another.

The article featured on this page is from the February 2010 issue of Mopar Enthusiast Magazine.